.. SPDX-License-Identifier: CC-BY-SA-4.0 Environment variables ===================== The libcamera behaviour can be tuned through environment variables. This document lists all the available variables and describes their usage. List of variables ----------------- LIBCAMERA_LOG_FILE The custom destination for log output. Example value: ``/home/{user}/camera_log.log`` LIBCAMERA_LOG_LEVELS Configure the verbosity of log messages for different categories (`more `__). Example value: ``*:DEBUG`` LIBCAMERA_LOG_NO_COLOR Disable coloring of log messages (`more `__). LIBCAMERA_IPA_CONFIG_PATH Define custom search locations for IPA configurations (`more `__). Example value: ``${HOME}/.libcamera/share/ipa:/opt/libcamera/vendor/share/ipa`` LIBCAMERA_IPA_FORCE_ISOLATION When set to a non-empty string, force process isolation of all IPA modules. Example value: ``1`` LIBCAMERA_IPA_MODULE_PATH Define custom search locations for IPA modules (`more `__). Example value: ``${HOME}/.libcamera/lib:/opt/libcamera/vendor/lib`` Further details --------------- Notes about debugging ~~~~~~~~~~~~~~~~~~~~~ The environment variables ``LIBCAMERA_LOG_FILE``, ``LIBCAMERA_LOG_LEVELS`` and ``LIBCAMERA_LOG_NO_COLOR`` are used to modify the default configuration of the libcamera logger. By default, libcamera logs all messages to the standard error (std::cerr). Messages are colored by default depending on the log level. Coloring can be disabled by setting the ``LIBCAMERA_LOG_NO_COLOR`` environment variable. The default log destination can also be directed to a file by setting the ``LIBCAMERA_LOG_FILE`` environment variable to the log file name. This also disables coloring. Log levels are controlled through the ``LIBCAMERA_LOG_LEVELS`` variable, which accepts a comma-separated list of 'category:level' pairs. The `level `__ part is mandatory and can either be specified by name or by numerical index associated with each level. The optional `category `__ is a string matching the categories defined by each file in the source base using the logging infrastructure. It can include a wildcard ('*') character at the end to match multiple categories. For more information refer to the `API documentation `__. Examples: Enable full debug output to a separate file, for every `category `__ within a local environment: .. code:: bash :~$ LIBCAMERA_LOG_FILE='/tmp/example_log.log' \ LIBCAMERA_LOG_LEVELS=0 \ cam --list Enable full debug output for the categories ``Camera`` and ``V4L2`` within a global environment: .. code:: bash :~$ export LIBCAMERA_LOG_LEVELS='Camera:DEBUG,V4L2:DEBUG' :~$ cam --list Log levels ~~~~~~~~~~ This is the list of available log levels, notice that all levels below the chosen one are printed, while those above are discarded. - DEBUG (0) - INFO (1) - WARN (2) - ERROR (3) - FATAL (4) Example: If you choose WARN (2), you will be able to see WARN (2), ERROR (3) and FATAL (4) but not DEBUG (0) and INFO (1). Log categories ~~~~~~~~~~~~~~ Every category represents a specific area of the libcamera codebase, the names can be located within the source code, for example: `src/libcamera/camera_manager.cpp `__ .. code:: cpp LOG_DEFINE_CATEGORY(Camera) There are two available macros used to assign a category name to a part of the libcamera codebase: LOG_DEFINE_CATEGORY This macro is required, in order to use the ``LOGC`` macro for a particular category. It can only be used once for each category. If you want to create log messages within multiple compilation units for the same category utilize the ``LOG_DECLARE_CATEGORY`` macro, in every file except the definition file. LOG_DECLARE_CATEGORY Used for sharing an already defined category between multiple separate compilation units. Both macros have to be used within the libcamera namespace of the C++ source code. IPA configuration ~~~~~~~~~~~~~~~~~ IPA modules use configuration files to store parameters. The format and contents of the configuration files is specific to the IPA module. They usually contain tuning parameters for the algorithms, in JSON format. The ``LIBCAMERA_IPA_CONFIG_PATH`` variable can be used to specify custom storage locations to search for those configuration files. `Examples `__ IPA module ~~~~~~~~~~ In order to locate the correct IPA module for your hardware, libcamera gathers existing IPA modules from multiple locations. The default locations for this operation are the installed system path (for example on Debian: ``/usr/local/x86_64-pc-linux-gnu/libcamera``) and the build directory. With the ``LIBCAMERA_IPA_MODULE_PATH``, you can specify a non-default location to search for IPA modules. n62'>62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242